


Thirst of miscalculation.

by Loverofyaoi22



Series: Submissive Error oneshots and stories. [9]
Category: Undertale (Video Game)
Genre: Endrogeny x Kobalt, Error x Lust, F/F, Finding Out Secrets, Lazulite x Nightmare x Dream, M/M, Multi, Vampires, bad ink, errotic - Freeform, powers, vampire!Underlust AU
Language: English
Status: In-Progress
Published: 2019-01-07
Updated: 2019-09-08
Packaged: 2019-10-06 07:13:06
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 3,369
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17340950
Author URL: https://archiveofourown.org/users/Loverofyaoi22/pseuds/Loverofyaoi22
Summary: Error goes to Underlust after a fight with ink only to be in the wrong place at the wrong time. To save his AU from dying if the secret got out, Lust turned Error into a vampire. But what happens when I k looks for Error after the fight and endangers Lust's mate? Lust was NOT having that!(You wanted this story so I'm giving it to you, so enjoy!)Pairings:Vampire!Lust x Vampire!ErrorVampire!Kobalt x Vampire!EndrodgenyNightmares x Vampire!Lazulite x Dream





	1. Error’s bloody discovery part 1.

**Author's Note:**

> I have had this written for ages and wanted to post it on wattpad but i left before i could. This is a gift for Gallifreyanpal as i know they love Errotic Nd they are a great writer

Error was not having a good day; not at all. He had been in Outertale just and star gazing in the dark abyss filled with colours, twinkling starts and awe inducing galaxies, when Ink showed up being an annoying twat. He came here when bored with watching Undernovela and knitting as there was hardly anything to do within that white endless void that was his home. He became friends with the frisk of Outertale who he called Starry and he talked to Outer too about the night sky. Ink would laugh at the insult he called called Error, huge paintbrush in hand. “You’re such a bother on this multiverse, why not vanish forever? I mean, no care about you, no one needs you, no one loves you; you’re nothing but unwanted leftover coding from something that no longer exists.” Ink laughed, girating on Error’s nerves and infuriating him.

Errors hand clenched into a tight fist. He knew this for god sakes, did he really have to always tell him this when he knew what he was?

After an hour of Inks bullshit, Error snapped. He pulled his blue strings from his eyee, fury making his marrow boil and his soul palpitate. “I’VE HAD IT UP TO HERE WITH YOU!!!” He shouted, turning to Ink with furious eyelights. Ink laughed darkly. Whenever Ink riled Error up and a fight commenced then he would call for help which came and he’d be forced to leave. The battle commenced; bones, lasers and paint flying everywhere as as blue strings. “WHY CAN”T YOU FUCK OFF AND LEAVE ME ALONE?!” Error shouted to the creator. In his strings was Ink’s paintbrush which he had taken and had been hurt by in many fights. 

Both their clothes were torn showing decorated and tri-coloured bones for the multiverse to see.

Ink laughed again, a sound Error loathed. His eyes became a red target and a red eye light; showing his anger. “Because i want to make you suffer, i want you to burn after everything you have ever done to this multiverse.” He growled and fired some red bones that Error didn’t expect. Errors eyes widened and pulled the huge paintbrush infront of his as a shield to take the impact. ‘You snidy little fucker!’ Error thought in shock and was slightly impressed.

The bones pierced the brush, cracking the wooden body of the brush badly and another surprise bone pierced through the already deep cracks, breaking it into tiny pieces that floated safely within a weave of blue strings and bones. ‘It....broke....’ he thought, eyes widening in shock. He never thought that the brush would finally break especially after so many battles.

A bristle poked his eye socket causing him to hold into it as he dislodged it. “”How dare you?!” Ink shouted in fury as his beloved brush broke into tiny fragmented pieces and making him snap his head up to look at the furious artist. “That’s it you filthy error!! I’m done with your bullshit!!” Error gulped as the other summoned a blaster. This blaster was huge; 5 times bigger than his open and it opened its huge jaws that showed a blue laser building up.

His soul began beating in fear. “Fuck You!” Ink shouted as he fired his blaster. Error gulped, eyes wide in fear. ‘Shit, i won’t be able to dodge it! He thought in panic. Within his tangled webbing of string, the brush pieces began to glow with a bright white light which formed a huge circular white, near opalescent barrier that absorbed inks attack and fired it back twice as hard.

Ink couldn’t believe that the broken remains of his brush protected his enemy even though he destroyed it and screamed in agony as the attack hit him and sent him flying. His bones became black and burned, some completely gone. The barrier spilled light into the dark scenery and Error stared at it in awe. It was so beautiful. With ink hurt, he saw his chance.

Error opened multiple portals and there the pieces -bar the bristle he held onto- into them and breaking the barrier. He quickly closed them before opening another one to leave. 

“Happy hunting bitch!” Error called as he rushed through the portal and closed it after himself. 

He sighed as he landed in a Snowdin mood some kind and panted; exhausted and hurt from the battle. The wet cold snow made his bones ache a bit but he didn't care. He was away from Ink. Little did he know he was in the wrong snowdin! “Hmm, such pretty bones~” a male voice purred from behind him making him gulp out of fear. He knew where he was. ‘Fuck, i’m in Underlust!’ Turning around he came face to face with a cat monster. The cat monster was male and around 6’2. He wore a simple pair of short leather shorts and nothing else showing off his white and brown fur to everyone. Dark lustful eyes looked him up and down. 

Error scrambled up off the floor and ran for it; rushing past the housing and sex shops. “Oh come on honey~i just want to taste your bones a blood~” the cat crooned and Error shuddered. ‘Oh HELL no!’ He thought in disgust and hid between some rubbish bins, holding onto his breath as the cat monster walked by. Luckily the bins covered his scent. “Oh, it;s you~” the monster said to someone Error couldnt see through the spaces between the bins. The person chuckled darkly. “You’re trying to hurt someone again.”

Error frowned. The voice sounded familiar but he couldn’t quite put his finger on it. The cat monster chuckled, smirking and one hand on his hip. “He was mine, i saw him first~ his black and red bones looked so succulent to bite and fuck as i sucked him dry~ god he smelled so delicious~” he purred in a sickening delight. Error shivered in disgust and fear. This guy wanted to touch and fuck him even if he didn’t want to. The monster he was talking to was not happy and pulled him away from view hissing “you’re gonna pay!”

The voice was pissed which made the destroyer confused. 

He waited for a while before coming out of from between the rubbish bins. He looked around the alley for any signs of someone. Nothing; there was no one. Sighing, he walked off again. “Never again am i coming to this AU.” He mumbled to himself, turning and corner and looking up.

His blood marrow run cold and his soul froze mid beat.

The scene he stumbled upon make him gasp and stumble back in horror at what he was seeing. This couldn’t be right! It just couldn’t be! This was just supposed to be a normal Underlust....right? It was Lust sans craning the others neck to the side with large pearly white fangs sunk deep within the other other monsters neck. Today just wasn’t Error’s day, was it?


	2. Error’s bloody discovery part 2.

**Summary for the Chapter:**

> Error is about to have a fun time.

Error sat there, shaking and glitches covering his body more and more out of fear. How was Underlust filled with fucking vampires and no one ever notice? He knew they were in a permanent state of heat but he didn’t know this! Did Ink even know about this?! Error never had a reason to be afraid of Lust before but now he definitely did.

Lust was drinking the others blood; the warm copper liquid flowing down his throat and into his stomach. He had been starving and he was in hunt for a meal from a friend but when he saw this piece of shit, he knew what he was gonna do. He was well know for threading others into having sex or raping people then hiding. Rapists in Underlust were given a public death usually but he was hungry so he’d drain the little fucker instead.

Lust ignored the misters small begs to stop, focusing his senses in sensing Error behind him who was paralysed with fear. He couldn’t help but mentally chuckle. He had always found the destroyer cute but seeing him afraid like this was adorable. Lust was a renounced alpha in Underlust and had a sadistic possessive streak so many tried to stay in his good books as possible.

Error stumbled back to his feet and tried to leave but tripped over his own feet and hit the ground with a loud thud. His legs felt like Jelly and he felt so scared.

Is that how people felt when he destroyed AUs?

Lust seemed to ignore him, just continuing to eat greedily despite how bad the other monster now looked. The cat monster looked weak and very sick; eyes glassy and unfocused. The once soft fur looked brittle to the touch and dry. He whimpered as the fangs dislodged from his skin and the skeleton glared darkly at the other; his heart eyes gone and revealing dark purple eyelights.

“P-please, let me go.” He whimpered but it fell of deaf ears. 

“You will never hurt anyone again~ you have raped and threatened countless people so no, I won’t let you go~” he purred as he snapped the others neck watching as the other turned to dust without so much of a flinch. He felt his LV go up to 19; which if most people checked him they’d see it.

Error had tears going down his face from utter horror. Sure, he had more LV and power than lust did but the fight had drained his magic ability bar portal making down to 0. Lust had drunk someone’s blood then killed them like it was nothing but an everyday occurrence. He was a vampire and fucking powerful one at that.

‘I’m gonna die, I’m gonna die!’ He thought.

Lusts dark giggle made him shudder and almost wet himself out of sheer terror. He really should have watched what Snowdin he had landed in after the fight with Inky! “So, you’ve found out our secret. “ he said lowly making the other scramble back as the other turned around; teeth stained red and walked over.

 

He was cowering and shaking vigorously at this point as the vampire pulled him up by his shirt and pinned him to a corner wall. He cried out in pain at the slam against the hard concrete. The tears began falling faster though they were silent. “Please....Don’t Hurt me.” Error whimpered. 

His magic could tell the other Here was an Alpha. He wasn’t an alpha, he was a powerful submissive so the alpha had full control.

Lust couldn’t believe how delicious the other smelt.

He smelt of chocolate, rain and blue raspberry; a beautiful concoction of scents to the vampire and the others soul he could claim as his own.

 

“You know too much. If this gets out then we’ll be hunted down and killed by Inky. I’ll keep you alive but at price. You’ll become mine~” He summoned the others soul out his rib cage. The sound of it beating and it’s erratic pace showed the fear. “N-no, don’t break my soul!”

 

“I’m not gonna break it pet~”

The soul was glitchy with dark blue strings to keep it secure and in one piece. The soul itself was light blue, dark yellow, light yellow and gold. Lust was entranced by its beauty; he had never seen such a beautiful soul before. “Hmm, JUSTICE, VENGEANCE, INTEGRITY AND ANGELIC. Quite the beautiful soul.” He said Seriously.

 

It was unique and it was one of a kind which he was not used to seeing. Error let out a sniff and a stuttering breath. His face was soaked and his nose ran. He didn’t want to die! 

 

Lust frowned at the mess the other had become and used his hand to wipe the yellow, dimly glowing tears away. “Shhh, I won’t kill you. I already said I’m not gonna kill you.” Error looked at him deep in the eyes. 

“But this might hurt.” Before Error could ask or freak out, Lust bit into his soul. It burned and he screamed in pain as fire erupted out in his body. It burned as the other drunk pure magic from his soul, the cumulation of his being. Lust moaned lightly. The other tasted so sweet and he wanted to eat it all but he had promised he wouldn’t kill Error; only turn.

 

Suddenly the pain vanished and Error began to feel very tired as the other the drunk his magic. Everything became dizzy and blurred together like he was deep underwater. Sounds became muffled and his sockets drooped. Where was he again? What had been doing? As he began to feel more and more sleepy he also began to feel very hungry.

Lust stopped and gently released the soul, fangs now coated in blood and yellow and blue magic. He licked the wound before gently biting down again and injecting venom into the soul to turn him. It burned again, even more now with the venom however Error gave gave a soft moan of pain. He was weak and hungry.

 

Error was starving and his stomach growled which lust heard and chuckled. The turning process did make the other very hungry. Vampire monsters didn’t turn others via biting the neck but the soul as the soul works magic and anything added to it round the body which makes the transformation quicker. 

When turned by a vampire, the one who turned you is your sire but can also become a mate as well. If away from the sire too long, it caused immense pain for the vampling; the term for a baby vampire or newly turned one. 

The sire and vamplings couldn’t be far away for the first month or so because vamplings couldn’t control their powers or urges.

 

As the venom took hold, Error gave a soft whimper. He wanted to eat! Lust giggled softly and let his skull. “Easy hun, I know you’re hungry.” He smiled as his mark finished forming on the others soul which was purple. The mark would tell others he was Errors alpha and sire and Error was his. He now had a vampling and a mate. A cute submissive mate at that.

Errors eyes were glassy, just like the cat monsters had been but they screamed exhaustion and hunger. He had the urge to sleep but he couldn’t yet. Alpha hadn’t fed him yet! They had one crucial step now; consuming his Alpha’s blood. 

This would complete and set the transformation in stone.

Lust used his fangs to cut his bottom lip and let the purple blood well up before kissing Error deeply. Error weakly kissed back, the blood going into his mouth. It tasted delicious and he began sucking in lusts bottom lip to drink more of the blood which the other didn’t complain about.

He ate it greedily, like he’d never eat again.

It was blood, blood that shouldn’t taste good or even be consuming but it tasted so good! He would panic but that had been replaced with hunger and drowsiness. After a while, the blood flow tapered off and Error lets his lip go. It was slightly swollen now but he didn’t care.

“Sleep now hun, you’re safe and it’s gonna be ok.” 

Error didn’t need telling twice and fell asleep at his Alpha’s command; slumping forward and into Lusts arms. Lust let his grip on Errors top go and chuckled, picking the other gently.

“Let’s get you home, my gemstone.” He clicked his fingers and teleported back home; leaving a pile of dust and shorts in the snow. Lust hummed as he opened the door to his house with magic and walked inside to the nice and warm home; well nice and warm for Error and stuffy for him. Being constantly warm was a horrid curse.

Pink and Mettaton stared at him startled. He had come home earlier than normal and now he had someone in his arms. They smelt and sensed the magic the gemstone covered skeleton was frowning in. Lusts but someone else’s they had never sensed before. “Brother, you’ve become a sire?!” Pink exclaimed in awe, helping Lust lay Error down on the soft sofa they had.

 

Pink was Mettatons mate and sire and had turned him ages ago so now the other lived with the brothers. Lust had learnt that Mettaton was a nice and calm person to be with; good at advice and was a councilor for people who had been raped, like he had been. He had a special shelter put up for rape victims where they could feel safe and could get help instead of being shamed; no matter if they were male or female. 

Lust had respect for the robot and couldn’t be happier his brother had found such an amazing man. 

“Yes I have. It’s to protect him and because he knows about our secret. If he tells anyone from other AUs, they’ll come here and slaughter us all. Just like they did with Vampiretale.” He said seriously. Pink gulped. Vampiretale had been raided by Ink and his army when they feared the inhabitants were with the dark sanses and slaughtered them all mercilessly. Error had been forced to find any survivors and hide them with Nightmare. 

From then in, they kept their distance from them all for their protection. “I understand. Was he attacked?” Pink asked, curious. Lust nodded. “Yeah; the rapist piece of shit Blythe tried to rape him but he managed to hide before he was even touched. The fucker is dead now, killed by own hand.”

Mettaton growled. Blythe had been the one to rape and attack most the people in his shelter and was so fucking glad he was dead. “Well He is dead now. Good job on making sure he can’t hurt anyone else.” Lust nodded as he undid Errors jacket and took top and shorts off to reveal his skeletal body. It was scarred to high heaven and they all winced.

Some of the, looked so grotesque.

“Oh god, gemstone who did this to you?” Lust mumbled as his brother rushed to get some hot soapy water and a rag to clean Error down with. He checked Error and frowned sadly at the scars. He would do anything to stop anymore from being added to his body.

“Here you go.” Pink said giving the bowl of water and the rag. “Thanks brother.” He said with a smile, dipping the rag into the water and lightly wringing it out before he began cleaning the blood, paint and dirt off the others body. The water turned a murky dark grey colour with a red hint and it disgusted hint hat no one saw how badly the other needed a bath.

He could also tell the other had been in a massive fight with Ink; the magic and paint of his body told him so. Anger flared up at fact Ink could hurt someone and would get away Scott free as it was seen for the greater good but if anyone else did it, then they would have dire consequences. 

Soon lust had finished cleaning the other and got him gently dried with a towel before putting him in white PJs which was a blinding contrast against his dark bones. It was beautiful in Lusts opinion but then again he had always found the destroyer beautiful.

Once dressed and Covered in s thick red blanket, he gently lifted the others lip up. He smiled at the small little fangs that were beginning to come through. The transformation was almost complete and he was glad he had a mate and someone to protect. If Error hadn’t been claimed, many would try to kill or rape him which he didn’t believe in. 

Soon the wings would be coming through but until then he could sleep knowing the other was asleep and safe. Getting up, he kissed Errors forehead gently. “Goodnight Gemstone. Sleep well.” He yawned and went upstairs to his room where he stripped down to his shorts and climbed into bed. Curling up in the thin covers, air conditioning going to keep him comfortable he fell asleep thinking about a certain gemstone coloured vampling.


End file.
